Electrical switch gear



July 5, 1932. w. ADAM ELECTRICAL swrrcn GEAR Filed Oct. 11, 1930 Inventor:

Walter Adam, b wMM H is Attorheg.

Patented July 5, 1932 U IT D STA ES WALTER ADAM,

PATENT ori ice OF BEBLI N-OBEBSCHENEWEIDE, GERMANY, ASSIGNOR T GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRICAL swrrcn GEAR Application filed October 11, 1930, Serial No. 488,146, and in Germany November 27, 1929.

My invention relates to electrical switc.h gear, and more particularly to means for isolating and covering the stationary disconnecting contacts of the truck or draw-out type of electrical switchgear.

. During the operation of disconnecting the movable draw-out switch unit with respect to the live stationary bus and feeder contacts, the movement,whether horizontal or vertical, of the switch unit or truck is generally ac:

companicd by a further isolating operation .wherein the stationary contacts connected to the live bus bars and other electrical connections are covered and enclosed by a shield or shutter-like arrangementso that the operator is protectedfrom coming into contact with live parts when the switch unit is Withdrawn from its operative connected position. It is also important that the stationarycontacts be effectively protected from dust or atmospheric influences whenin the isolated position so that the contacting surfaces thereof shall not be corroded or coated with material increasing the contact resistance. In appa- .l ratus of the character abov'edescribed it is the usual practice to arrange the isolating shutter apparatus with respect to the movable or vertical to the axis of the casing or housing within which the stationary isolating contacts are mounted. When the cross section of this housing is of circular or elliptical cross section, asis oftenthe case, the seating surface for the shutter corresponds to a mathematically complicated curve which involves obvious difficulties in designand construction. A further disadvantage of thisarrangement resides in the fact that the shutter when closed does'not necessarily seat tightly on the housing since pressure is not exerted to force the shutter firmly on to itsseat.

My invention has for its principal objectrangement for stationary isolating contacts which shall have means for biasing the shutter directly against its seat in the closed position thereof and for moving the shutter directlyaway from its seat prior to its uncovering movement during the opening operation thereof.

In accordance with my invention the housing for the stationary isolating contacts may be constructed with the usual-cylindrical or elliptical cross section and the shutter may comprise a simple plate-like member adapted to cover and fit tightly over the open end of'the housing when in the isolating position. For the purpose of operating the shutter, there is employed a lever system related to the movable switch'unit in such a manner that during the opening movement of the shutter it is at first moved approximately in a straight line substantially perpendicular to the seating surface and is then moved in a lateral or the stationary isolating contact.

My invention will be more fully set forth in the following descriptionreferring to the accompanying drawing and the featuresof novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

the provision of an improved shutter ar-' sidewise direction so as completely to uncover v connected and disconnected positions withrespect to the stationary structure 1. The stationary structure in the present instance comprises a plurality of housings or casings 3 for the live busses and feeders (not shown) which are insulated in any suitable manner with respect to the enclosing housings. The stationary disconnecting or isolating contacts (not shown) are electrically connected in any suitable manner to the busses and are individually mounted within housings l, 5 and 6 of suitable cross section, as cylindrical or the like, which are open at their outer ends and adapted to be closed by the cover or shutter members 7, 8 and 9 respectively. In the housings 4: and 5 are disposed the stationary isolating contacts connected to the busbars whereas the isolating contact for the outgoing line or feeder is arranged in the housing 6.

The movable draw-out truck unit 2, on which is mounted a switch (not shown), as an oil circuit breaker, comprises the movable isolating or disconnecting contacts 10, 11 and 12 for coacting with the stationary isolating contacts arranged within the housings l, 5 and 6 respectivly. The movable contacts are mounted on and move as a unit with the truck which is usually mounted upon wheels so that it may be rolled into operative or inoperative position.

F or the purpose of operating the shutter members '7, 8 and 9 so that they will auto matically open to uncover the isolating contacts when the movable truck unit 2 is moved into operative position, and vice versa, there is provided a lever system for each shutter comprising a bellcrank 13 pivotally mounted on the corresponding housing and pivotally connected at one end at 13 to a lever 1% having a sliding connection, by reason or" the slot 15, with a fixed pin 16 also mounted on the housing. At the outer end of the lever 14 is mounted the corresponding shutter comprising plate member biased firmly when in t 1e cl position as illustrated in Fig. 1 against the outer edge of the contact enclosing housing by the spring 17 which is connected at one end to the housing and at its other end to the lever l-l. One of the bellcranlrs 13 is connected with an operating member or crank 18 for coaction with an actuating member or lug 19 mounted and carried by the movable truck unit 2, the bellcranlzs 13 being interconnected by the links 20 and 21 for insuring simultaneous operation thereof.

Assuming that the switchgear is in the position illustrated in Fig. 1 and that the movable unit 2 is to be moved int-o operative position wherein the movable contacts 10, 11 and 12 are in engagement wita their coacting contacts, movement of the switch unit towards operative position causes the actuating member or lug 19 to engi the operating member 18 at the recess i so that continued movement of the truck unit causes simultaneous rotation through the interconnecting lever mechanism of the bellcranlrs 1.3. Since the initial rotative movement of the iiiotal connection 13 of each the bias of spring 17. As the rotative movement of the bellcrank 13 is continued, refer-ring to a single shutter mechanism, the

link 1% continues to move outwardly by reason of the slot 15 and starts to pivot about the pin 16 as illustrated in Fig. In this position, the shutter has moved a sullicient distance away from its seat so that it may be moved laterally in a pivotal manner without obs ruction. \Vhen the shutter has moved to a position so that the toggle formed by the lever 14L and the bellcrank 13 has passed the dead center position, the spring 1? acts to pull the shutter to the position illustrated in Fig. 3 and to retain it in such position until it is positively actuated by the movable truck unit towards the covering or isolating position. In the position illustrated in Fig. 3, the shutter is disposed along the outer side of the corresponding housing so that it is entirely out of the way and occupies but little space when the switch unit is in operative position.

ll hen the truck unit 2 is withdrawn to its isolating position, the reverse operation is performed, the member 19 serving to cam the operating member 18 in a countcrclocle wise direction and to insure simultaneous operation of the shutters to the closed position illustrated in Fig. 1 wherein the shutters are each firmly biased by the spring 17 towards their seating surfaces so that dust or gases in the surrounding air are cited tively precluded from coming into contact with the stationary contacts. As in the uncovering operation, the springs 17 act to complete the operation after the toggle above clescribed has passed dead center. Accordingly, the actuating lug 19 need only eilect part of the covering and uncovering operations since the springs are effective to complete the final part of the operations. It desired, the springs 1'? may be replaced by a single spring of suflicient strength coacting with the interconnecting lever mechanism for operating the bellcranks as a unit.

It shall be understood that my invention is not limited to the specific truck type switchgear herein illustrated but is equally applicable to other draw-out or drop-down types wherein a movable switch unit is provided with isolating contacts for coaction with the stationary contact structure,

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art Without departing from the spirit of my invention.

lVhat I claim as new and desire to secure by Letters Patent of the United States is:

1. In electrical switchgear including a stationar bus structure having isolating con-' I member directly against its seating surface with said housing when it is in the isolating position, and means coacting with said movable unit for moving said cover member longitudinally away from its seat and then lateral ly to the uncovering position. p c

2. Inelectrical switchgear including stationary bus structure having disconnecting contacts for coacting with contacts carried by a switch unit movable with respect to said bus structure, isolating meansfor covering each of said stationary disconnecting contacts when said switch unit isinthe isolated disconnecting position thereof comprising a cover member operable to a position for isolating said stationary disconnecting con tact, means coacting with said movable unit for imparting pivotal movement to said member during part of the isolating opera tion, and means for biasing said cover'member in a linear direction in its isolating position.

3. In electrical switchgear including a stationary bus structure having disconnecting contacts for coacting with movable disconnecting contacts carriedby a switch unit movable with respect to said stationary struc 'ture and an enclosing housing for each stationary disconnecting contact open at one end for receiving the coacting movable disconnecting contact, means for covering and isolating each of said stationary disconnecting contacts when said switch unit is in the inoperative disconnecting position comprising a cover member adapted to seat at the open end of said housing, a lever having a sliding connection for moving said cover member pivotally and then longitudinally into seating position, and means connected to said lever coacting with said movable unit for causing closing of said cover member to isolating position when the switch unit is withdrawn and for moving said memberto uncovered position when said unit is moved into operative position,

4. Isolating structure for stationary disconnecting contacts coacting with movable disconnecting contacts carried by a movable switch unit comprising an enclosing housing for each of said stationary contacts, said housing being open at one end for receiving the coacting movable contact, and a platelike cover member pivotally and reciprocally mounted with respect to said housing whereby said cover member may be pivotally ,moved from a lateral position and thereupon longitudinally moved against its seating surface at the open end of said housing to effect isolation of said contact, and a lever mechanism coacting with said movable unit for causing opening and closing of said cover member in accordance with the position of said unit. I

' 5. Isolating structure for stationary disconnecting contacts coacting with a movable switchunit, comprising a contact enclosing housing, a platelike member for covering one end of said housing in the contact isolating position, a lever connected to said member adapted for pivotal and longitudinal movement, means connected tosaid lever coacting with said movable unit for causing longitudinal movement of said member away'from its seating surface during the initial opening movement thereof and for thereafter imparting pivotal movement to said member for moving the same laterally to open position.

6 Isolating structure for the stationary disconnecting contacts of truck-type switchgear including a movable switch unit, comprising a cover member adapted to be moved to an isolating position, a lever connected to said cover member for moving the same into and out of the isolating position, said lever being provided with a pin and slot connection for permitting pivotal and reciprocal movements thereof, resilient means acting on said lever to bias said cover member into firm seating position in the isolating position thereof, and means including a crank connected to said lever coacting with said movable unit for imparting longitudinal movement to said cover member with respect to its seat against the bias of said resilient means and for also imparting an uncovering pivotal movement thereto in response to movement of said unit to operative position,

7 Isolating structure for the stationary disconnecting contacts of truck-type switchgear including a' movable switch unit, comprising an enclosing housing open at one end for each of the stationary contacts, a cover member pivotally and reciprocally mounted movable laterally over the open end of each of said housings, linkages interconnecting said cover members for insuring simultaneous operation thereof, spring means for biasing said cover members in a longitudinal direction against the seating surfaces thereof in the isolating position and for likewise maintaining the cover members in open position, and a crank operatively connected to said linkages coacting withsaid movable 'unit for causing simultaneous operation of said cover. members in accordance with the position of said movable unit, each of said cover members being actuated in a longitudina'l direction with respect to its seat when moving into and from isolating position.

8. In electrical switchgear including stationary disconnecting contacts and a movable switch unit cooperating therewith, isolating structure for each of said stationary disconnecting contacts comprising an enclosing housing open at one end, a plate-like cover adapted to seat on the open end of said housing in the isolating position, a lever mounted on said housing for pivotal and longitudinal movements, said lever operatively connected to said cover, a crank connected to said lever forming a toggle therewith, a spring operatively connected to said toggle for biasing said cover into either the open or isolating position thereof, and an actuating member carried by said movable switch unit coacting with said cranlrfor causing operation of said cover in accordance with the position of said unit.

In witness whereof, I have hereunto set my hand this 29th day of September, 1930.

WALTER ADAM. 

